This invention relates to the resolution or breaking of oil-in-water emulsions. Specifically, the invention relates to chemical means for resolving such emulsions.
Various waters such as "produced water" from oil wells and various industrial water waste streams will be in the form of emulsions which have an internal "oil" phase, generally present as very small droplets. For environmental or other reasons it is frequently desired to resolve or "break" these emulsions to separate the oil phase from the water phase. The most common method of resolving such emulsions is the addition of a chemical demulsification compound.
One approach at a chemical demulsifier is the use of zinc salts such as zinc chloride. However, the use of zinc or other heavy metals is of considerable environmental concern and poses its own disposal problems. Further, the zinc salts are corrosive toward metal pumps, tanks, and drums.
Another approach is the use of certain tridithiocarbamic acid compounds as described in U.S. Pat. No. 4,826,625 (Thompson - Petrolite; 1989). However, this approach has limited applicability, depending on the nature of the oil and the pH of the water.